Added pixelRatio option to override canvas upscaling. Resolves #876, test included...

[dygraphs.git] / auto_tests / tests / hidpi.js

diff --git a/auto_tests/tests/hidpi.js b/auto_tests/tests/hidpi.js
index c595065..ceb3a49 100644 (file)
--- a/auto_tests/tests/hidpi.js
+++ b/auto_tests/tests/hidpi.js
@@ -3,21 +3,24 @@
  *
  * @author danvdk@gmail.com (Dan Vanderkam)
  */
-var hidpiTestCase = TestCase("hidpi");
+
+import Dygraph from '../../src/dygraph';
+
+describe("hidpi", function() {
+
+cleanupAfterEach();
 
 var savePixelRatio;
-hidpiTestCase.prototype.setUp = function() {
+beforeEach(function() {
   savePixelRatio = window.devicePixelRatio;
   window.devicePixelRatio = 2;
+});
 
-  document.body.innerHTML = "<div id='graph'></div>";
-};
-
-hidpiTestCase.prototype.tearDown = function() {
+afterEach(function() {
   window.devicePixelRatio = savePixelRatio;
-};
+});
 
-hidpiTestCase.prototype.testDoesntCreateScrollbars = function() {
+it('testDoesntCreateScrollbars', function() {
   var sw = document.body.scrollWidth;
   var cw = document.body.clientWidth;
 
@@ -38,7 +41,40 @@ hidpiTestCase.prototype.testDoesntCreateScrollbars = function() {
   // Adding the graph shouldn't cause the width of the page to change.
   // (essentially, we're checking that we don't end up with a scrollbar)
   // See http://stackoverflow.com/a/2146905/388951
-  assertEquals(cw, document.body.clientWidth);
-  assertEquals(sw, document.body.scrollWidth);
-};
+  assert.equal(cw, document.body.clientWidth);
+  assert.equal(sw, document.body.scrollWidth);
+});
+
+it('should be influenced by options.pixelRatio', function () {
+  var graph = document.getElementById("graph");
+
+  // make sure devicePixelRatio is still setup to not 1.
+  assert(devicePixelRatio > 1.5, 'devicePixelRatio is not much greater than 1.');
+
+  var data = "X,Y\n" +
+    "0,-1\n" +
+    "1,0\n" +
+    "2,1\n" +
+    "3,0\n";
+
+  // first try a default one
+  var g1 = new Dygraph(graph, data, {});
+  var area1 = g1.getArea();
+
+  var g2 = new Dygraph(graph, data, { pixelRatio: 1 });
+  var area2 = g2.getArea();
+
+  var g3 = new Dygraph(graph, data, { pixelRatio: 3 });
+  var area3 = g3.getArea();
+
+  assert.deepEqual(area1, area2, 'areas 1 and 2 are not the same');
+  assert.deepEqual(area2, area3, 'areas 2 and 3 are not the same');
+
+  assert.notEqual(g1.canvas_.width, g2.canvas_.width,
+    'Expected, for devicePixelRatio != 1, '
+    + 'that setting options.pixelRatio would change the canvas width');
+  assert.equal(g2.canvas_.width * 3, g3.canvas_.width,
+    'Expected that pixelRatio of 3 vs 1 would triple the canvas width.');
+});
 
+});